Optically reflective pcb

Abstract

A head up display system presents a virtual image to a human driver of a motor vehicle. A picture generation unit includes a printed circuit board having at least one light emitting device emitting light from a surface of the printed circuit board. The surface has an optically reflective coating. A liquid crystal display receives the emitted light and reflects a portion of the received emitted light back to the printed circuit board. The optically reflective coating of the printed circuit board reflects the light reflected by the liquid crystal display back to the liquid crystal display. At least one mirror reflects light passed by the liquid crystal display toward a windshield of the motor vehicle such that the light is reflected by the windshield and is visible to the human driver as the virtual image.

What is claimed is: 
     
         1 . A head up display system for presenting a virtual image to a human driver of a motor vehicle, the system comprising:
 a picture generation unit including:
 a printed circuit board having at least one light emitting device configured to emit light from a surface of the printed circuit board, the surface having an optically reflective coating; and 
 a liquid crystal display configured to receive the emitted light and reflect a portion of the received emitted light back to the printed circuit board, wherein the optically reflective coating of the printed circuit board is configured to reflect the light reflected by the liquid crystal display back to the liquid crystal display; and 
   at least one mirror configured to reflect light passed by the liquid crystal display toward a windshield of the motor vehicle such that the light is reflected by the windshield and is visible to the human driver as the virtual image.   
     
     
         2 . The system of  claim 1  wherein the optically reflective coating is configured to reflect over 90 percent of the light reflected by the liquid crystal display back to the liquid crystal display. 
     
     
         3 . The system of  claim 2  wherein the optically reflective coating comprises an aluminum coating. 
     
     
         4 . The system of  claim 1  wherein the picture generation unit includes a first lens disposed between the printed circuit board and the liquid crystal display. 
     
     
         5 . The system of  claim 4  wherein the picture generation unit includes a collimating lens disposed between the first lens and the liquid crystal display. 
     
     
         6 . The system of  claim 5  wherein the printed circuit board, the collimating lens, the first lens, and the liquid crystal display are substantially parallel to each other. 
     
     
         7 . The system of  claim 1  wherein the at least one mirror comprises a plurality of mirrors. 
     
     
         8 . A method for presenting a virtual image to a human driver of a motor vehicle, the method comprising:
 providing a printed circuit board including a surface having an optically reflective coating;   emitting light from the surface of the printed circuit board;   using a liquid crystal display to receive the emitted light and reflect a portion of the received emitted light back to the printed circuit board;   using the optically reflective coating of the printed circuit board to reflect the light reflected by the liquid crystal display back to the liquid crystal display; and   using at least one mirror to reflect light passed by the liquid crystal display toward a windshield of the motor vehicle such that the light is reflected by the windshield and is visible to the human driver as the virtual image.   
     
     
         9 . The method of  claim 8  wherein the optically reflective coating reflects over 90 percent of the light reflected by the liquid crystal display back to the liquid crystal display. 
     
     
         10 . The method of  claim 9  wherein the optically reflective coating comprises an aluminum coating. 
     
     
         11 . The method of  claim 8  further comprising providing a first lens between the printed circuit board and the liquid crystal display. 
     
     
         12 . The method of  claim 11  further comprising providing a collimating lens disposed between the first lens and the liquid crystal display. 
     
     
         13 . The method of  claim 12  wherein the printed circuit board, the collimating lens, the first lens, and the liquid crystal display are substantially parallel to each other. 
     
     
         14 . The method of  claim 8  wherein the at least one mirror comprises a plurality of mirrors. 
     
     
         15 . A picture generation unit for a head up display system that presents a virtual image to a human driver of a motor vehicle, the picture generation unit comprising:
 a printed circuit board including at least one light emitting device configured to emit light from a surface of the printed circuit board, the surface having an optically reflective aluminum coating; and   a liquid crystal display configured to receive the emitted light and reflect a portion of the received emitted light back to the printed circuit board, wherein the optically reflective aluminum coating of the printed circuit board is configured to reflect the light reflected by the liquid crystal display back to the liquid crystal display, wherein light passing through the liquid crystal display is reflected so as to be visible to the human driver as the virtual image.   
     
     
         16 . The picture generation unit of  claim 15  wherein the optically reflective aluminum coating is configured to reflect over 90 percent of the light reflected by the liquid crystal display back to the liquid crystal display. 
     
     
         17 . The picture generation unit of  claim 15  wherein the picture generation unit includes a first lens disposed between the printed circuit board and the liquid crystal display. 
     
     
         18 . The picture generation unit of  claim 17  wherein the picture generation unit includes a collimating lens disposed between the first lens and the liquid crystal display. 
     
     
         19 . The picture generation unit of  claim 18  wherein the printed circuit board, the collimating lens, the first lens, and the liquid crystal display are substantially parallel to each other. 
     
     
         20 . The picture generation unit of  claim 15  wherein the surface of the printed circuit board is substantially planar.